Magneto-electric generator.



1 -R.H.GUNN1NGHAM;

MAGNETO ELECTRIC GENERATOR.

H I APPLIUATIOH $11.31) 00T.B,1912-. 1,098,431.

Patented June 2, 191.4-

2 SHEETS-SHEET 1 WITNESSES INVENTOR R. H. GUNNINGHAM.

MAGNBTO ELECTRIC GENERATOR.

APPLICATION FILED OUT. 8, 1912.

1,098,431; Patnfied June 2,19%

2 SHEETS-SHEET 2.

1m 1sn WITNESSES Z Y BY 2 ATTORNEY UNITED s ATEs PATENT OFFICE.

RICHARD H. CUNNINGHAM, OF NEW YORK, N. Y., ASSIGNOR 'I'O SPLITDORF -ELECTBIGAL COMPANY, OF NEWARK, NEW JERSEY.

MAGNETO-ELECTRIC GENERATOR.

Specification of Letters Patent.

To all whom it may concern:

Be it known that I, RICHARD H. CUNNING- HAM, a citizen of the United States, a resident ofNew York city, borough of Manhattan, in the county of New York and State of New York, have invented certain new and useful Improvements in Magneto-Electric Generators; and I do hereby declare the following to be a full, clear, and exact description of my invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to magneto-electric generators employed for ignitlon purposes in connection with internal combustion engines, and more particularly to generators adapted for use in connection with that class of engine which is commonly employed to propel motor bicycles, motor tricycles, and small four wheeled motor vehicles. When such engines are of the two cylinder type, the two piston rods usually act on a common crank and the axes of the two cylinders, which are disposed in the plane of the crank, converge toward the axis of the crank shaft; the angular inclination between said cylinder axes varying according to the design of the engine. The explosive mixture in the respective cylinders should be fired at the points of maximum compression in said cy inders and the respective cycles of one cylinder should follow those of the other at an angular interval as close as possible to 360 deg. The angular disposition of the cylinders however necessitates a variation in this interval so that it becomes alternately greater and, less than 360 deg. by an amount equal to the angle between the cylinder axes. In other words, if the angular inclination of the cylinders to each other be denoted by the symbol X, the explosions will occur at an interval of 360 deg. :X, and since the armature of the two pole magneto must rotate at half crank-shaft speed to produce sparks at periods corresponding to the proper explosive cycle, the sparks produced by the action of the ma etc should occur at intervals of 180 deg. i- As an ordinary magneto with symmetrically shaped pole pieces and a symmetrical H-shaped armature yields symmetrical positive and negative current half waves with their maxima separated by an interval of 180 deg, it is evident that in order to produce current half waves with max1ma separated byintervals of 180deg.

Patented June 2, 1914..

;i;%, a distortion of one or of both half I waves must occur. Now, it is a well established fact that every distorted wave, or half wave, is the result of the combination of a fundamental wave with a su erimposed harmonic or harmonics of a di erent periodicity, which may or may not be in phase with the fundamental wave. Hence it is evident that by superimposing a harmonic or harmonics of the proper frequency and amplitude upon the usual fundamental wave or preferably upon alternate half waves such as are ordinarily produced by a magneto alternating current generator, it is possible to produce a distorted wave the maxima of the positive and negative half waves of which will occur at intervals approximately equal to 180 degi provided that the angle X is comparatively small.

It is the object of my invention to produce this requisite distortion of one or the other current half wave or half waves or both, and in my companion application, Serial No. 724,528, filed Oct. 8, 1912, such distortion is effected by modifying the contour of the pole pieces and rotatable part in a novel manner.

In the exemplification of my invention shown in the accompanying drawings, the magnetic portion or portions of the magnetic armature are shaped difierently than heretofore. The usual shape for a magnet-o being like the letter H. My improved construction has the magnetic poles of the armature inclined so they resemble the letter H with the sides tipped or inclined toward each other on one side of the horizontal and diverging on the other side. Excellent results are obtained when the inclination of the sides or oles are approximately equal to one half of the angle between the engine cylinder. I'also reduce and shape the ma netic field poles and provide a suitable win ing to cooperate therewith, so that by the revolution of such rotatable part in the magnetic field between the pole pieces every other result-ing current half wave is so distorted that the maxima ofthe two half waves occupy such a position with reference to each or -eras to approximately fulfilthe coriiitions required by the formula 180 deg.

In the drawings which form a part hereof,

the same reference characters designate like parts throughout the several views Figure 1 is a transverse section of a magneto taken' a; right angles to the axis of the armature;- diagrammatically showing the magnetic pole arcs, and thegasymmetrically' field magnets being shown, with the arma-.

ture in the neutral position, or where the change in magnetic lines is 1227, and the terminal E. M. F. is zero. Fig. 3 shows the armature revolved to a position where one ofthe rotating pole tips is about to break away from one of the pole pieces, producing a slight change in the magnetic flux. Fig. 1 shoWs the rotating part in a-position in which one of the pole tips has entirely broken away from the field pole and the second tip isabout ready to break away from its trailing field pole, or at nearly the point producing a maximum potential in the reverse direction from Fig. 1. Fig. 5 shows the rotating part in its second neutral position, the terminal voltage being back at zero. Fig. 6 is a diagrammatic representation of the primary circuit current wave framed by such a magneto in operation, and illustrates the irregular shapes of the positive and neg ative values of the wave with certain maxima displaced the required number of degrees.

Referring to Fig. 1, the armature or rotatable part designated 1 may be built up if desired of laminations or thin sheets of magnetic material, or may be constructed of a solid piece of magnetic material, or a combination of solid pieces, and laminations, the laminations in the latter case being preferably laced at the center of the rotating part. he parts of the armature may be held together in any. suitable manner.

2 and 3 represent the magnetic pole pieces which are associated with the permanent magnets 4. The pole piece 2 has a shorter arc than the pole piece 3. In my preferred form I use a primary Winding 5 and a secondary winding 11, so connected as to produce the desired result. The primary winding is usually connected in a short circuit, through an interrupter, the same as shown in my Patent 1021506, with a condenser bridged across the interrupter points, the same .as shown in Fig. 5 of my Patent 1023552. I do not limit myself, however,

to this particular arrangement of winding, as I may use a single coil which may or may not be placed onthe rotating element, as

my invention is broad enough to include. what is known as the 'inductorl type of generator. I a

6 illustrates the means of filling up the space between the normal to the main 'portion of the rotating element and the inclined pole tips, 7 and 8.

-9 illustrates the axis of rotation of the rotatable element. 10 illustrates the axis of the coilitself, these axes being in different planes. I obtain excellent results by tipping each of the pole pieces of the rotating element at an angle approximately equal to one-half the angle between the engine cylinders, and one of the pole pieces reduced to an amount substantially such that the pole tips of the rotating element will just span the are between the field. poles as illustrated in Fig. 1.

Considering now the actions of magnetic flux, and current wave, and referring to Fig. 6 in connection with the respective diagrammatic representations of the magneto parts, the point 12, or approximately thereto, corresponds to the position of the rotating element shown in Fig. 1, so that when this element is being rotated in the directionindicated .by the arrows in the corresponding figures, from the position indicated in Fig. 1 to that indicated in Fig. 2, the current wave will rise from point 12 to 13 somewhat abruptly, and then die down to zero more gradually, the maximum point 13 being produced by.a slight rotation in the direction of arrow shown in Fig. 1. Continued rotationof the rotatable element to the position of Fig. 3 will cause the current wave to pass through zero at the point 14:, and begin to cause a current flow in the reverse direction. As the pole tip 7 leaves the pole piece 2 a secondary crest will be formed, and as the element continues to rotate to the position of Fig. 4, the wave will ascend until pole tip 8 breaks away from the pole piece 3, when the maximum point 16 is reached. Further rotation of the rotatable element to the position of Fig. 5 produces a portion of the current wave from 16 to 17, and thence to point 12, thus completing a full cycle or an angular interval from 12 to 12, or from 13 to 13' of 360degrees. It will be evident from an inspection of the diagram shown in Fig. 6 that if a line 18 be drawn midway between the points 13 and 13, the distance from a line 19 drawn through point 13, both said lines being perpendicular to the base line, to said line 18 will correspond to an interval of 180 deg. A line 20 drawn parallel to 18 and 19, through point 16, will be spaced from line 18 by an angular interval substantially corresponding .to g, and hence the current wave generated by the means :ibove described meets the required condions.

In the preferred form of my invention it will be observed that the magnetic material of the rotatable element is asymmetrical with respect to a lane passing through and 'longitudmal of t e armature and at right angles to the lane of the coil, and includin the axis 0 rotation of the armature, as we 1 as a corresponding plane including the axis of the coil. By axis of the 'coil is meant, the line about which the coil rotates, while it is being wound. This line is the broken line .10, shown in Fig. 1. By plane of the coil is meant, a plane corresponding to the plane of rotation of the coil while it is being wound. It will be seen that this plane will be at right angles to the axis of rotation of the coil above.

referred to, and will be parallel with the sides of the coil, which are adjacent members 6, which fill up the sides between the pole tips and the sides of the coil.

In general I have shown that the asymmetrical disposition of the magnetic material in the rotary and stationary arts of a magnetic-electric generator is e ective to produce awave which is non-sine in form, and composed of a fundamental, and one or more harmonics, and displaced in the manner described. By means of this construction, I am enabled, further, to vary the maximum rate of change of flux corresponding to one half wave With respect to that corresponding to the next since as will be seen upon inspection of Fig. 6, the contour of the half waves adjacent the crests 13 and 16 are difierent, and this difference may be increased or diminished by varying the superimposed harmonics, which may readily be accomplished by rendering the transverse cross-section of the magnetic portions of the armlature and poles more or less asymmetrica.

While I have shown a preferred form of my invention, I do not wish to be limited by the exact details shown therein, as I am aware that numerous changes and alterations may be made, all of which I believe will come within the scope of the appended claims.

Having thus described my invention, What I claim 1s':-

1. In a magneto-electric generator, magnetic material disposed to form a path for the magnetic flux, said material including magnetic pole pieces and an armature, and a coil adapted to be electrically influenced by changes in the magnetic flux through said material, the pole pieces of the armature beingdivergent on one side, and con vergent on the other side of the main portion of said armature, said first named magsides of the armature and being asymmetrical with respect to each other.

2. In amagneto-electricj enerator, magnetic material disposed to orm a path for the magnetic flux, said material including,

of, substantially as, and for the purpose described.

3. In a magneto-electric generator, the

combination of magnetic material disposed to form a path for the magnetic flux, said material including magnetic pole pieces of unequal arcs, a rotating part, and a coil adapted to be electrically influenced by changes in said magnetic flux, through said material, pole pieces of said rotating part being tilted from the normal to said rotating part, the. axis of said rotating part being in a difierent plane than the axis of said coil.

4;. In a magneto-electric generator, permanent magnets having opposed pole pieces of unequal arcs, each pole piece 'ofitself being of uniform section transversely throughout its length, an armature therebetween, and a conducting coil on said armature, the pole pieces of said armature being tipped from the normal to the main portion of said' armature substantially as,

' and for the purpose described.

.5. In a magneto-electric generator, the combination of a source of magnetic flux, field pole pieces of unequal arcs, associated with said source, a rotatable part producing changes in the magnetic flux, a coil adapted to be electrically influenced by changes in said magnetic flux, the field pole pieces and the magnetic material of said rotatable part being asymmetrically arranged with respect to the axis of the coil,

6. In a magneto-electric generator, magnetic material disposed to form a path for the magnetic flux, said material including magnetic pole pieces, a rotatable part, and a coil adapted to be electrically influenced by changes in the magnetic flux, said magnetic pole pieces being of unequal length of arc and said rotatable part having pole pieces of equal length of are but inclined fromthe normal to the main portion of said armature, substantially as described.

7. In a magneto-electric generator, the combination of permanent magnets, pole pieces therefor, a rotating element and a coil adapted to be electrically influenced by the changes in the magnetic flux due to said rotating element, said magnet pole pieces being of unequal arcs, and said rotating element having equal pole pieces, inclined from the normal to the main portion of said rotating element throughout their entire length, whereby the magnetic material of said rotatable element is asymmetrically arranged with respect to its axis of rotation netic material disposed to form a path for the magnetic flux, said material comprising fixed parts and a rotatablepart, a conductive coil disposed adjacent to said material,

and adapted to be electrically influenced by changes in said magnetic flux, the magnetic material of said fixed part being of-unequal arcs, and the magnetic material in the rotatable part having pole pieces with inner faces in the same straight line and inclined to the normal to the main portion of said rotatable part, whereby rotation of the rotatable part will produce a current wave in said coil which is different from a sine wave.

In testimony whereof I atfix my signature in the presence of two witnesses RICHARD H. CUNNINGHAM. Witnesses:

JAMEs M. WILSON, FRANK H. MAHER. 

